Which UPS to buy ?

This is a discussion on Which UPS to buy ? within Gadgets, Computers & Software, part of the Shifting gears category; My dad purchased and got installed a Microtek 1500 EB inverter with two Exide batteries (dont know specifications as I ...

My dad purchased and got installed a Microtek 1500 EB inverter with two Exide batteries (dont know specifications as I was not there during purchase).

When the installation was done, and the house was running on battery, my computer's APC UPS would not switch on. If the main was on, then APC would switch on. From main if auto changeover to battery, APC would still be on. But while running on batteries, if I switch on the PC, the APC ups would switch off and go on a loop on off on off (yellow light).

I can run the PC and loads of other appliances on battery. But why is APC ups not running on the inverter load? Because of this I have plugged in the PC directly to the wall socket.

Today there was a small fluctuation in power (went off and on in a milisecond). The computer got switched off. When I was using APC UPS, it would handle such minor fluctuations.

To me it appears that your inverter is getting overloaded when you switch on the computer. The output voltage of the inverter may be dropping and the low voltage cutoff of your UPS turns it off. With the computer load cut off, the inverter voltage raises again and your UPS comes on only to cut off again. This process repeats.

Try switching off all other loads in the house and check whether you can run the computer to confirm the above diagnosis. You must know the VA rating of your Inverter and try to limit the total load within its rated capacity.

^^^It may not be just due to the load. APC will fall to battery mode whenever it finds the input current to be unacceptable. This may mean that the waveform of the output of your Microtek is beyond the tolerance level of the UPS and hence it switches to battery mode.

This may mean that your Microtek is not good stuff. Is it a sine wave inverter btw? Even if it says so, its probably not. I use a quasi sine wave SuKam + Amaron Sheild with my APC UPS and they get along ok.

^ashwinsid has very clearly mentioned that his APC UPS switches on and off ( hunting ) when the inverter is on battery mode and the computer is switched on. The APC UPS remains on when the computer is off. Please read the post carefully.

First he has to make sure that his inverter is not getting overloaded and its output voltage is not coming down. ( This itself may prove to be due to the poor quality of the inverter as one would normally expect the inverter to cut off when overloaded.)

Oops, sorry. Guess in the hurry, I didn't go thru it carefully. In that case, it may be due to overload. It may also be due to weak batteries.

Edit :- But there is another issue - he has mentioned simply switching on the UPS does not work. Simply switching it on should not create any load on the inverter. After switching it on, load would come in the picture when the CPU and monitor are turned on. So again, it may not be due to load but due to unacceptable output from the inverter.

Let us not break our heads. ( I must admit here that ashwinsid has not defined the problem very clearly and what he has stated could be misinterpreted differently by different persons with two battery-powered devices in play.)

Let ashwinsid switch off all loads, switch off Mains power and let the inverter take over. Under this condition where his computer is going to be the only load on the inverter, let him switch on the APC UPS and then the computer and report the status.

@Ponmayilal , @Raccoon , thanks for the insight guys. To make it easy for me to explain, I will list this in points:

1. All other appliances in the house are off. Even PC, the APC UPS is off.
2. The mains are ON (electricity board). I switch on APC, switch on PC. Fine.
3. To check, I switch off mains and now inverter takes over.(while PC is running)
4. Immediately APC UPS goes from green light to amber blinking. PC will be ON but APC will be not normal.
5. I switch ON the mains again and now APC comes back to normal green.
6. Now mains are ON. APC is ON but PC is off.
7. I switch off mains and inverter takes over.
8. APC UPS is normal green.
9. Now while the APC UPS is running on inverter, I switch on PC immediately APC starts the amber light blinking.
10. If I switch off pc still APC will be blinking.

So if APC is on and PC is off, even when inverter takes over APC will be ON.
If APC is off and when inverter is on, then if i try to switch on APC, it will blink amber.

The inverter is not sinewave. I was not involved in the purchase decision :(

I asked the inverter guy why is this and he had no answer. He said similar thing happened in another house and dont know why computer UPS wont run on Inverter.

I shall now agree with Raccoon that it is not load related but due to unacceptable output from the inverter. to Raccoon.

Suggested solutions:

1. Ask the supplier to replace the unit to check if the problem is resolved. (It is quite possible that the unit supplied may be off-specifications and you got a lemon.)

2. If the same problem persists even with a new unit, insist on the supplier to take back the unit and refund the purchase cost. Insist on the point that other company products do not exhibit such problems and as such his machine is not suitable for you. If you can demo it from a unit borrowed from a friend, it will be all the more convincing. ( Make sure the battery input voltage for that unit is the same as the Microtek unit. Either 12V or 24 V).

On a finer point, just check that there is no Live-Neutral reversal when switched from Mains to Inverter.

My dad purchased and got installed a Microtek 1500 EB inverter with two Exide batteries (dont know specifications as I was not there during purchase).

When the installation was done, and the house was running on battery, my computer's APC UPS would not switch on. If the main was on, then APC would switch on. From main if auto changeover to battery, APC would still be on. But while running on batteries, if I switch on the PC, the APC ups would switch off and go on a loop on off on off (yellow light).

I can run the PC and loads of other appliances on battery. But why is APC ups not running on the inverter load? Because of this I have plugged in the PC directly to the wall socket.

Today there was a small fluctuation in power (went off and on in a milisecond). The computer got switched off. When I was using APC UPS, it would handle such minor fluctuations.

What to do? How do I run the APC ups on inverter?

The inverter and APS ups are not compatible , the computer/APS UPS needs pure sine wave to operate . The inverter may be giving sine wave output ,but might not be accurate one (clean ,or maybe not a good engineered ) ...something like that .

There is one more angle some time it happens , if you connect the inverter directly to computer without UPS , there are chances the computer SMPS might not kick in , because the SMPS and inverter is not compatible. This too can happen.

These problems can occur when the input sensing frequency of the UPS is not compatible with the output freqency of the inverter of if the outpuf waveform is not clear. you can ask the manufacturer or rectify it. but since it is a new system I recommend you to ask them to replace it, a different system will have a different output frequency. Same problems can occur when using generators. These problems are more frequent in microcontrolled systems.

I require your inputs for me to finalize the UPS model as well as specs. My criterias are as below :

1) It should to the least simultaneously power 2 fans, 3 Tubelights, Laptop Charger, Modem and Wireless router, TV
2) Are there UPS's available to power on the Refrigerators as well ?
3) 24x7 support and quick turn around to problems

I require your inputs for me to finalize the UPS model as well as specs. My criterias are as below :

1) It should to the least simultaneously power 2 fans, 3 Tubelights, Laptop Charger, Modem and Wireless router, TV
2) Are there UPS's available to power on the Refrigerators as well ?
3) 24x7 support and quick turn around to problems

My friend has bought Luminuous and has positive feedback.

Seeking the forum members' thoughts !

You are talking about inverter ?. what is your backup requirement in hours.
1. It depends on the wattage of your tv. 2 fans, 3 tubes, and one 21 inch TV makes about 400 Watts. check the wattage on your modem, laptop charger, and router adapter. I think it will be about 100 watts. so a total of 500 watts. Since it is not recommended to run a inverter in full load, you will need a 750 or 800 Watt inverter.
750 and 800 watt inverter usually require only one battery.

2. inverters are available for fridge, but it needs usually more than 1000W alone. so you will need 2 batteries, that is double the expense. I think you are need it for an office.
3. 24x7 service is specific to brands in the specific region. It is different in banglore and in cochin. ask your friends or other forum members for that region.

Luminuous, su-kam, xenon are good brands. browse through this thread for more info.

My dad purchased and got installed a Microtek 1500 EB inverter with two Exide batteries (dont know specifications as I was not there during purchase).

When the installation was done, and the house was running on battery, my computer's APC UPS would not switch on. If the main was on, then APC would switch on. From main if auto changeover to battery, APC would still be on. But while running on batteries, if I switch on the PC, the APC ups would switch off and go on a loop on off on off (yellow light).

I can run the PC and loads of other appliances on battery. But why is APC ups not running on the inverter load? Because of this I have plugged in the PC directly to the wall socket.

Today there was a small fluctuation in power (went off and on in a milisecond). The computer got switched off. When I was using APC UPS, it would handle such minor fluctuations.

What to do? How do I run the APC ups on inverter?

Hi Ashwinsid, Hope my response is not too late! I had a similar problem - i have a Sukam Pure sine wave Inverter and a Frontech UPS and the UPS will trip whenever I tried switching on my desktop (with a CRT monitor). If the desktop was already ON I did not have any issues. If my monitor goes into powersave mode and if it comes back again then UPS will trip. I guess it is due to the power surge when you switch on the CRT monitor. You have two options: Plug the CRT alone directly into power outlet and the CPU to the UPS else try and get a TFT monitor which will not have a power surge so the UPS will not trip.

You are talking about inverter ?. what is your backup requirement in hours.
1. It depends on the wattage of your tv. 2 fans, 3 tubes, and one 21 inch TV makes about 400 Watts. check the wattage on your modem, laptop charger, and router adapter. I think it will be about 100 watts. so a total of 500 watts. Since it is not recommended to run a inverter in full load, you will need a 750 or 800 Watt inverter.
750 and 800 watt inverter usually require only one battery.

2. inverters are available for fridge, but it needs usually more than 1000W alone. so you will need 2 batteries, that is double the expense. I think you are need it for an office.
3. 24x7 service is specific to brands in the specific region. It is different in banglore and in cochin. ask your friends or other forum members for that region.

Luminuous, su-kam, xenon are good brands. browse through this thread for more info.

I have very similar requirements and I thought I have to get a UPS if I need un-interruptible supply of power. Is this (uninterruptible supply) possible with an Inverter also? For same capacity which one of the two is cheaper?